Building an expert system is known as knowledge engineering and its practitioners are called knowledge engineers. The knowledge engineer must make sure that the computer has all the knowledge needed to solve a problem.
The knowledge engineer must choose one or more forms in which to represent the required knowledge as symbol patterns in the memory of the computer that is, he (or she) must choose a knowledge representation.
He must also ensure that the computer can use the knowledge efficiently by selecting from a handful of reasoning methods.
The practice of knowledge engineering is described later.
We first describe the components of expert systems.